Circuit for a catheter or sheath and method of forming same

ABSTRACT

A circuit ( 10, 110, 210 ) configured for connecting an electrode ( 28, 126, 228 ) to a catheter or sheath is disclosed. The circuit ( 10, 110, 210 ) includes a member ( 12, 112, 212 ) having a longitudinal axis ( 14, 214 ) and configured to extend along at least a portion of the length of the catheter or sheath. The circuit ( 10, 110, 210 ) further includes a trace ( 16, 116, 230 ) printed on the member ( 12, 112, 212 ), where the trace ( 16, 116, 230 ) includes at least a longitudinal segment ( 18, 118 ) extending generally along at least a portion of the longitudinal axis ( 14, 214 ) and a transverse segment ( 20, 120 ) extending generally transverse to the longitudinal axis ( 14, 214 ). In an embodiment, the circuit further includes a pad ( 26, 126, 226 ) integral with and extending from the ( 10, 110, 210 ) proximal the transverse segment ( 20, 120 ) of the trace ( 16, 116, 230 ). A catheter or sheath assembly comprising the circuit ( 10, 110, 210 ) and an electrode ( 28, 126, 228 ) connected to the circuit ( 10, 110, 210 ) is also disclosed. A method of forming a catheter or sheath assembly is also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application No.60/828,939, filed 10 Oct. 2006, which is hereby incorporated byreference as though fully set forth herein.

BACKGROUND OF THE INVENTION

a. Field of the Invention

The instant invention relates to a circuit for a catheter or sheath,including a circuit with a trace printed on the circuit and configuredfor connection to an electrode.

b. Background Art

Catheters have been in use for medical procedures for many years.Catheters can be used for medical procedures to examine, diagnose, andtreat while positioned at a specific location within a body that isotherwise inaccessible without more invasive procedures. During theseprocedures a catheter is commonly inserted into a vessel near thesurface of the body and is guided to a specific location within the bodyfor examination, diagnosis, and/or treatment. For example, one procedureoften referred to as “catheter ablation” utilizes a catheter to conveyan electrical stimulus to a selected location within the human body tocreate tissue necrosis. Another procedure often referred to as “mapping”utilizes a catheter with sensing electrodes to monitor various forms ofelectrical activity in the human body.

Catheters are also used increasingly for medical procedures involvingthe human heart. Typically, the catheter is inserted in an artery orvein in the leg, neck, or arm of the patient and directed, sometimeswith the aid of a guide wire or introducer, through the vessels until adistal tip of the catheter reaches the desired location for the medicalprocedure in the heart.

A typical human heart includes a right ventricle, a right atrium, a leftventricle, and a left atrium. The right atrium is in fluid communicationwith the superior vena cava and the inferior vena cava. Theatrioventricular septum separates the right atrium from the rightventricle. The tricuspid valve contained within the atrioventricularseptum provides communication between the right atrium and the rightventricle.

In a normal heart, contraction and relaxation of the heart muscle(myocardium) takes place in an organized fashion as electro-chemicalsignals pass sequentially through the myocardium from the sinoatrial(SA) node, which comprises a bundle of unique cells disposed in the wallof the right atrium, to the atrioventricular (AV) node and then along awell-defined route, which includes the His-Purkinje system, into theleft and right ventricles. The AV node lies near the ostium of thecoronary sinus in the interatrial septum in the right atrium. Each cellmembrane of the SA node has a characteristic tendency to leak sodiumions gradually over time such that the cell membrane periodically breaksdown and allows an inflow of sodium ions, thereby causing the SA nodecells to depolarize. The SA node cells are in communication with thesurrounding atrial muscle cells such that the depolarization of the SAnode cells causes the adjacent atrial muscle cells to depolarize. Thisresults in atrial systole, wherein the atria contract to empty and fillblood into the ventricles. The atrial depolarization from the SA node isdetected by the AV node which, in turn, communicates the depolarizationimpulse into the ventricles via the bundle of His and Purkinje fibersfollowing a brief conduction delay. The His-Purkinje system begins atthe AV node and follows along the membranous interatrial septum towardthe tricuspid valve through the atrioventricular septum and into themembranous interventricular septum. At about the middle of theinterventricular septum, the His-Purkinje system splits into right andleft branches which straddle the summit of the muscular part of theinterventricular septum.

Sometimes abnormal rhythms occur in the heart, which are referred togenerally as arrhythmia. For example, a common arrhythmia isWolff-Parkinson-White syndrome (W-P-W). The cause of W-P-W is generallybelieved to be the existence of an anomalous conduction pathway orpathways that connect the atrial muscle tissue directly to theventricular muscle tissue, thus bypassing the normal His-Purkinjesystem. These pathways are usually located in the fibrous tissue thatconnects the atrium and the ventricle. Another arrhythmia is ventriculartachycardia (“V.T.”). VT is a disease of the ventricles of the heart inwhich the heart's normal arrhythmic contraction is altered. Frequently,the rate of heart beat is too fast, although the conditions of thedisease itself are generally quite complex. VT may occur most often inpatients following a myocardial infarction. A myocardial infarction,commonly referred to as a heart attack, is a loss of blood to a regionof the heart causing the myocardial tissue in that region to die and bereplaced by an area of scar tissue known as a myocardial infarct.Frequently, the myocardial infarct is present in the left ventricle. Asa result of the myocardial infarct, circular pathways (“reentrycircuits”) are frequently created within the left ventricle whichconduct electrical impulses of the heart. These reentry circuits maycause the electrical impulses of the heart to travel in circles aboutthe myocardial infarct, frequently causing an erratic and sometimesaccelerated beating of the heart. These reentry circuits may also occuraround discrete elements of the heart, such as valves. In addition, thereentry circuits sometime occur around both the myocardial infarct andthe discrete elements of the heart.

Other abnormal arrhythmias sometimes occur in the atria, which arereferred to as atrial arrhythmia. Three of the most common atrialarrhythmia are ectopic atrial tachycardia, atrial fibrillation, andatrial flutter. Atrial fibrillation can result in significant patientdiscomfort and even death because of a number of associated problems,including the following: an irregular heart rate, which causes patientdiscomfort and anxiety; loss of synchronous atrioventricularcontractions, which compromises cardiac hemodynamics, resulting invarying levels of congestive heart failure; and stasis of blood flow,which increases the likelihood of thromboembolism.

Efforts to alleviate these problems in the past have includedsignificant usage of pharmacological treatments. While pharmacologicaltreatments are sometimes effective, in some circumstances drug therapyhas had only limited effectiveness and is frequently plagued with sideeffects, such as dizziness, nausea, vision problems, and otherdifficulties.

An increasingly common medical procedure for the treatment of certaintypes of cardiac arrhythmia and atrial arrhythmia involves the ablationof tissue in the heart to cut off the path for stray or improperelectrical signals. Such procedures are performed many times with anablation catheter. Typically, the ablation catheter is inserted in anartery or vein in the leg, neck, or arm of the patient and threaded,sometimes with the aid of a guidewire or introducer, through the vesselsuntil a distal tip of the ablation catheter reaches the desired locationfor the ablation procedure in the heart (endocardial ablation). Ablationmay also be performed from outside the heart (epicardial ablation) usingdevices introduced into the chest. The ablation catheters commonly usedto perform these ablation procedures produce lesions and electricallyisolate or render the tissue non-contractile at particular points in thecardiac tissue by physical contact of the cardiac tissue with anelectrode of the ablation catheter and application of energy. The lesionpartially or completely blocks the stray electrical signals to lessen oreliminate arrhythmia.

Another medical procedure using ablation catheters with sheaths toablate accessory pathways associated with W-P-W utilizing both atransseptal and retrograde approach is discussed in Saul, J. P., et al.,“Catheter Ablation of Accessory Atrioventricular Pathways in YoungPatients: Use of long vascular sheaths, the transseptal approach and aretrograde left posterior parallel approach,” Journal of the AmericanCollege of Cardiology, Vol. 21, no. 3, pgs. 571 583 (1 Mar. 1993). Othercatheter ablation procedures are disclosed in Swartz, J. F.,“Radiofrequency Endocardial Catheter Ablation of AccessoryAtrioventricular Pathway Atrial Insertion Sites,” Circulation, Vol. 87,no. 2, pgs. 487 499 (February 1993).

Ablation of a specific location within or near the heart typicallyrequires the precise placement of the ablation catheter. Precisepositioning of the ablation catheter is especially difficult because ofthe physiology of the heart, particularly because the heart continues tobeat throughout the ablation procedures. Commonly, the choice ofplacement of the catheter is determined by a combination ofelectrophysiological guidance and fluoroscopy (placement of the catheterin relation to known features of the heart, which are marked byradiopaque diagnostic catheters that are placed in or at knownanatomical structures, such as the coronary sinus, high right atrium,and the right ventricle).

The energy necessary to ablate cardiac tissue and create a permanentlesion can be provided from a number of different sources. Originally,direct current was utilized although laser, microwave, ultrasound, andother forms of energy have also been utilized to perform ablationprocedures. Thermal ablation catheters have also been used. Duringthermal ablation procedures, a heating element, secured to the distalend of a catheter, heats thermally conductive fluid, which fluid thencontacts the human tissue to raise its temperature for a sufficientperiod of time to ablate the tissue.

Conventional ablation procedures utilize a single distal electrodesecured to the tip of an ablation catheter. Increasingly, however,cardiac ablation procedures utilize multiple electrodes affixed to thecatheter body. These ablation catheters often contain a distal tipelectrode and a plurality of ring electrodes. Mapping catheters alsooften contain a plurality of sensing electrodes to monitor various formsof electrical activity in the human body. Sheaths may be provided forthe placement and translation of an ablation or mapping catheter in abody cavity. Sheaths may also be provided with one or more electrodesfor mapping of an endocardial or epicardial surface, for example.

Ablation and mapping catheters are labor-intensive to assemble. Eachelectrode must be individually brazed to a conductor, holes must bepunctured into the catheter shaft, each conductor must be threadedthrough the catheter shaft, and the electrodes must be slid into theirposition along the catheter shaft. Some ablation and mapping cathetersmay have up to 20 electrodes that need to be spaced in a particularconfiguration. Assembling the electrodes may take up to or even morethan approximately 45 minutes. Sheaths configured to include electrodesmay be similarly labor-intensive to assemble.

Thus, there remains a need for improving the timing for production andease of manufacture for an electrode assembly for a catheter or sheath,as well as increasing the reliability of the electrodes on the catheteror sheath, without sacrificing the ability of the catheter or sheath tobe deflected.

BRIEF SUMMARY OF THE INVENTION

It is desirable to be able to remove the multi-conductor wiring from acatheter or sheath, since multi-conductor wiring is highlylabor-intensive and results in an increased assembly time. It is alsodesirable to be able to indicate the desired locations of the electrodeson the catheter or sheath prior to assembly to further speed up assemblytime. It may also be desirable to increase the reliability of theelectrodes on the catheter or sheath by making the electrodes integralwith the conductor to prevent any unreliability that may be associatedwith the weld between discrete electrodes and conductors. Finally, itmay be desirable to modify the design of a conductor for a catheter orsheath without sacrificing the ability of the catheter or sheath to bedeflected, which is necessary for the applications of each.

A circuit configured for connecting an electrode to a catheter or sheathis provided. The circuit includes a member having a longitudinal axisand configured to extend along at least a portion of the length of thecatheter or sheath. The circuit further includes a trace printed on themember, where the trace includes at least a longitudinal segmentextending generally along at least a portion of the longitudinal axisand a transverse segment extending generally transverse to thelongitudinal axis. The circuit further includes a pad integral with andextending from the circuit proximal the transverse segment of the trace.A catheter or sheath assembly comprising the circuit and an electrodeconnected to the circuit are also provided. A method of forming acatheter or sheath assembly is also provided comprising the steps ofproviding a circuit, connecting an electrode to the circuit, andreflowing a plastic material over the assembly for maintaining placementof the circuit and the electrode in the assembly.

The foregoing and other aspects, features, details, utilities, andadvantages of the present invention will be apparent from reading thefollowing description and claims, and from reviewing the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a circuit and electrodes for use with acatheter in accordance with a first embodiment of the invention.

FIG. 2 is a perspective view of a circuit and electrodes for use with acatheter in accordance with a second embodiment of the invention.

FIG. 3 is a front cross-sectional view of a circuit and electrodes foruse with a catheter in accordance with the second embodiment of theinvention.

FIG. 4 is a side cross-sectional view of a circuit and electrodesembedded in a catheter in accordance with the first or second embodimentof the invention.

FIG. 5 is a top plan view of a circuit for use with a catheter or sheathin accordance with a third embodiment of the invention.

FIG. 6 is a perspective view of a circuit and electrodes for use with acatheter or sheath in accordance with a third embodiment of theinvention.

FIG. 7 is a front cross-sectional view of a circuit and electrodes foruse with a catheter or sheath in accordance with a third embodiment ofthe invention.

DETAILED DESCRIPTION OF THE INVENTION

A circuit configured for connecting an electrode to mapping and ablationcatheters or to sheaths is provided in which no discrete wiring isrequired. In accordance with a first embodiment, circuit 10 may beprovided for use with a mapping or ablation catheter. Referring to FIG.1, circuit 10 may include member 12. Member 12 may have a longitudinalaxis 14. Member 12 may extend along at least a portion of the length ofthe catheter. In some embodiments, member 12 may extend along a majorityof or even substantially along the entire length of the catheter. Atleast a portion of member 12 may generally be flat prior to use in acatheter. A majority of member 12 or substantially all of member 12 maygenerally be flat prior to use in a catheter in some embodiments. Atleast a portion of member 12 may be generally flat when in use in acatheter. A majority of member 12 or even substantially all of member 12may generally be flat when in use in a catheter in some embodiments.Referring again to FIG. 1, member 12 is illustrated as generally flat.Member 12 may be approximately 0.030″ in width. Of course, dependingupon the intended application, member 12 may have a larger or smallerwidth in some embodiments.

Circuit 10 may be configured to be disposed along a center of theopening of a catheter. Location of circuit 10 along the center of acatheter in the neutral axis may prevent undue stress from being placedon circuit 10 when the catheter is deflected. A neutral axis isgenerally defined as the axis in the cross-section of the catheter shaftalong which there are no longitudinal stresses and/or strains. Somecatheters may include a planarity ribbon wire extending along at least aportion of the length of the catheter in order to aid the catheter indeflection along a single axis. Circuit 10 may be configured to replacethe planarity ribbon wire. In some embodiments, circuit 10 may be ofincreased thickness when it is configured to replace the planarityribbon wire.

Circuit 10 may comprise a material that is flexible in order to allowfor deflection of the catheter, or sheath in some embodiments. However,circuit 10 may also comprise a material that is of sufficient rigidityto maintain the electrical integrity of the circuit. Circuit 10 maycomprise a polymer or plastic. For example, circuit 10 may comprisepolyimide or polyethylene terephthalate polyester. In some embodiments,circuit 10 may comprise KAPTON® or MYLAR® available from E.I du Pont deNemours and Company.

Circuit 10 includes a trace 16 included (e.g., printed) on member 12.The trace may comprise platinum or gold or copper (e.g., copper platedwith platinum, gold, or silver). Trace 16 may include a longitudinalsegment 18 extending generally along the longitudinal axis 14 of member12 and a transverse segment 20 extending generally transverse to thelongitudinal axis 14. The proximal end of longitudinal segment 18 oftrace 16 may originate at a solder pad that is compatible with a circuitconnector conventional in the art (e.g., a zif type connector). Trace 16may be about 0.002″ to about 0.003″ in width. Of course, depending uponthe intended application, trace 16 may have a larger or smaller width.Trace 16 may also be disposed between a first and second layer ofinsulation, with the trace and insulating layers being about 0.003″ toabout 0.008″ in thickness. Again, depending upon the intendedapplication, trace 16 and the insulating layers may be more or lessthick. Member 12 may include a plurality of traces. For example, member12 may include three traces as illustrated in FIG. 1. Member 12 mayinclude fewer or more traces. If member 12 includes a plurality oftraces, the longitudinal segment of each trace may extend a differentlength along longitudinal axis 14 of member 12, so that the eachtransverse segment is disposed at a different length along member 12.For example, longitudinal segment 22 of a second trace illustrated inFIG. 1 is a different length than longitudinal segment 18 of trace 16.Transverse segment 24 of a second trace illustrated in FIG. 1 istherefore at a different location along the length of member 12.Accordingly, a plurality of electrodes may be connected to circuit 10proximal the transverse segment of each trace at different locationsalong the length of member 12. Circuit 10 may include other tracepatterns (e.g., where the trace does not extend along the longitudinalaxis or transverse to the longitudinal axis, but at any number of anglesor directions).

Circuit 10 may include a pad 26 extending beyond the edge of member 12.Pad 26 may be integral with member 12. Pad 26 may extend from member 12proximal the transverse segment 20 of trace 16. The transverse segment20 may terminate into pad 26 in an embodiment. Pad 26 may extendgenerally transversely from longitudinal axis 14 of member 12. Pad 26may be configured for connection to electrode 28. Pad 26 may comprise abuilt-up or heavy solder pad which may be formed around the cathetershaft so that it may be configured for contact with the inner surface ofelectrode 28. Pad 26 may generally be smaller in width than electrode28. Pad 26 may also be of sufficient length to allow for properpositioning of electrode 28 over it.

Electrode 28 may be provided on the catheter for ablation or mapping.For example, electrode 28 may emit an electrical stimulus to createtissue necrosis and/or electrode 28 may comprise a sensing electrode tomonitor various forms of electrical activity in the human body. In anembodiment, electrode 28 may comprise a ring or a band. Accordingly,electrode 28 may include both an inner surface and an outer surface. Inan embodiment, electrode 28 may be approximately 7 French (e.g., about0.030″) in cross-sectional dimension. Electrode 28 may have a larger orsmaller cross sectional dimension in some embodiments. The width ofelectrode 28 may, for example, be about 1.5 mm. Of course, depending onthe intended application, electrode 28 may have a larger or smallerwidth. For some embodiments, electrode 28 may be comprised of platinum.Electrodes 28 may be welded to pad 26. For example, electrodes 28 may belaser welded to pad 26. Pad 26 may have about 0.005″ of solderdiscretely positioned on it so that electrode 28 may be soldered inplace once it has been positioned over pad 26. During assembly, laserenergy may be focused onto the outer surface of electrode 28 to create asolder puddle which would solder itself to the inner surface ofelectrode 28. Electrode 28 may further be connected to circuit 10 usinga conductive adhesive.

Referring now to FIG. 2, a circuit 110 in accordance with a secondembodiment of the invention is provided. Circuit 110 may besubstantially similar to circuit 10, including member 112 and trace 116,but circuit 110 may include a ring extension or pad 126 that iscomparatively wider and longer than pad 26. For example, ring extensionor pad 126 may be about 1.5 mm wide and have a length about equal to thecircumference of a 7 French catheter (e.g., about 0.30″). Ring extensionor pad 126 may be configured to form an electrode ring or pad forablation and/or mapping applications. Pad 126 may be biocompatible andmay be of sufficient composition and/or density to facilitatevisualization under fluoroscopy. Pad 126 may comprise gold or platinumand, depending upon the intended configuration, may not be masked. Forexample, pad 126 may comprise gold or platinum plating that is about0.0015″ to about 0.0020″ thick. Pad 126 may be integral with member 112.Pad 126 may extend from member 112 proximal a transverse segment 120 oftrace 116. The transverse segment 120 may terminate with or into pad126. Pad 126 may extend generally transversely to the longitudinal axisof member 112. Further, pad 126 may be configured to be formed (e.g.,rolled) into a ring to form an electrode for use in connection with thecatheter. The formed pad 126 may be adhesive-backed to allow forpositioning on the catheter shaft (e.g., 7 French catheter). During thereflow processing, the catheter or sheath shaft may be bonded to thecircuit 110 to hold it in position. In some embodiments, circuit 110 maybe fabricated with approximately one to twenty pads, each pad configuredto be formed or rolled into a ring to form a portion of an electrode. Iffewer electrodes were required in a catheter or sheath assembly than onthe fabricated circuit, then the extra pads 126 could easily be removed(e.g. cut-off). In some embodiments, two or more circuits 110 could beutilized in tandem to achieve the desired number of pads for forming thedesired number of electrodes or electrode portions.

Referring now to FIG. 3, circuit 110 may be disposed along the neutralaxis of the catheter. Accordingly, a first pull wire 130 may be disposedon a first side of member 112, and a second pull wire 132 may bedisposed on a second (e.g., diametrically opposing) side of member 112.In an embodiment as generally illustrated in FIG. 3, the first andsecond pull wires 130, 132 may be disposed generally alongside acenterline of member 112.

Referring now to FIG. 4, after each electrode is connected (i.e.,whether by connector or initial formation as part of the circuit) tocircuit 10 (or 110), the entire catheter shaft can be formed (e.g.,reflowed with material) in order to seal and/or secure the placement ofcircuit 10 (or 110) and the electrodes 28 (or 126). The electrodes 28(or 126) may be bonded and/or adhered to the shaft during the reflowprocess. The reflow material 34 may comprise plastic. In an embodiment,the reflow material 34 may comprise polyether block amides. In anembodiment, the reflow material 34 may comprise PEBAX®. However, duringdeflection of the catheter or sheath, the electrodes may loosen (i.e.,the circuit 10, 110 away from the electrodes 28, 126 may be pulled andcompressed, causing the circuit to move, push back, and even buckle.Placement of the circuit 10, 110 in spaghetti tubing may be utilized toallow for some movement (e.g., slight movement) of the circuit withinthe catheter or sheath shaft to try to prevent buckling. For example,without limitation, the spaghetti tubing may comprisepolytetrafluroethylene (PTFE) and may be disposed between the circuit10, 110 and the material of the shaft of the catheter or sheath. For acircuit with more complicated geometry, holes may need to be provided inthe spaghetti tubing to allow for protrusion of the pads or rolledelectrodes. As shown in FIG. 4, the catheter may further include a tip36 configured for tissue ablation. Referring still to the embodimentillustrated in FIG. 4, a first electrode 28 may be disposed, forexample, about 2 mm away from the ablation tip 36. A second electrode 38may be disposed, for example, about 5 mm away from the first electrode28. A third electrode 40 may be disposed, for example, about 2 mm awayfrom the second electrode 38. Additional electrodes may be disposed inthe same pattern along the length of the catheter. The distance betweenthe ablation tip and the electrode and/or between adjacent electrodesmay be greater or less then 2 mm or 5 mm in connection with otherembodiments.

In accordance with a third embodiment, circuit 210 may be provided foruse in connection with a mapping or ablation catheter and/or a sheathand/or another tubular object configured for insertion into a bodycavity or blood vessel. Referring now to FIGS. 5 and 6, circuit 210 mayinclude a member 212. Member 212 may have a longitudinal axis 214.Member 212 may extend along at least a portion of the length of thecatheter or sheath. In some embodiments, member 212 may extend along amajority of or even substantially the entire length of the catheter orsheath. At least a portion of member 212 may generally be flat prior touse in a catheter or sheath as shown in the embodiment generallyillustrated in FIG. 5. A majority of member 212 or even substantiallyall of member 212 may generally be flat prior to use in a catheter orsheath in some embodiments.

Referring again to FIGS. 5 and 6, member 212 may include a firsttransverse segment 216 extending generally transverse to longitudinalaxis 214. Member 212 may include a first longitudinal segment 218extending generally along at least a portion of longitudinal axis 214.Member 212 may include a second transverse segment 220 extendinggenerally transverse to longitudinal axis 214. Member 212 may include asecond longitudinal segment 222 extending generally along at least aportion of longitudinal axis 214. First and second longitudinal segments218 and 222 may be configured to be disposed on opposing sides of acatheter or sheath (e.g., approximately 180° apart). Further, at least aportion of member 212 may be curved when it is embedded within acatheter shaft or a sheath. A majority of member 212 or evensubstantially all of member 212 may be generally curved when it isembedded with a catheter shaft or sheath. In an embodiment, eachtransverse segment (e.g., 216, 220) may extend approximately one-half ofthe circumference of the catheter or sheath. In other embodiments, eachtransverse segment (e.g., 216, 220) may extend less than one-half of thecircumference of the catheter or sheath or more than one-half of thecircumference off the catheter or sheath. Each transverse segment (e.g.,216, 220) may be configured to be about one-half of the circumference ofa 7 French size catheter or sheath. However, each transverse segment maybe configured to be used with any size catheter or sheath (e.g., 6French or 5 French size catheter or sheath). Member 212 may include apad 226. Pad 226 may be substantially aligned with transverse segment216 and may extend generally transversely to the longitudinal axis 214of member 212. In the third embodiment, pad 226 may be configured forconnection to an electrode 228 similar to the first embodimentillustrated in FIG. 1. In a fourth embodiment, pad 226 may be configuredto be rolled or otherwise formed into an electrode similar to theconfiguration illustrated in FIG. 2. Member 212 may comprise a materialthat is flexible in order to allow for deflection of the catheter orsheath. Member 212 may also comprise a material that has sufficientrigidity to maintain the electrical integrity of the circuit. Member 212may comprise a polymer or plastic. For example, without limitation,member 212 may comprise polyimide or polyethylene terephthalatepolyester. In some embodiments, member 212 may comprise KAPTON® orMYLAR®.

Referring again to FIGS. 5 and 6, pad 226 may have a reduced profileand, depending upon the intended circumstance or application, may not bemasked to provide connection to another component (e.g., an electrode).In some embodiments, electrodes 228 may be welded (e.g., laser welded)to pads 226 substantially as described in connection with circuit 10 inthe first embodiment. In other embodiments, pads 226 may besubstantially thicker and longer as described in connection with circuit110 in the second embodiment such that pads 226 may be configured to berolled or otherwise formed into an electrode.

Still referring to FIG. 5, member 212 may comprise a plurality oftransverse and longitudinal segments and a plurality of pads. Forexample, illustrated member 212 includes six transverse segments, fourof which are aligned with four pads, as illustrated in FIG. 5. Member212 further includes six longitudinal segments as illustrated in FIG. 5.Member 212 may include fewer or more transverse and longitudinalsegments. Each of the transverse segments may be disposed at a differentlength of member 212 so that each electrode may be disposed at adifferent location along the length of member 212. In an embodiment,pads 226 may be spaced, for example, approximately 10 mm apart along thelength of member 212. In other embodiments, pads 226 may be spacedcloser or further apart.

Member 212 may include a trace 230. Trace 230 may, for instance,comprise platinum or gold or copper (e.g., copper plated with platinum,gold, or silver). The proximal end of trace 230 may originate at asolder pad that is compatible with a circuit connector conventional inthe art (e.g., a zif type connector). The trace may extend along each ofthe longitudinal segments and each of the transverse segments of member212. Trace 230 may terminate with, at, or about pad 226. Additionaltraces may be printed on member 212 if member 212 includes additionalpads to which electrodes are or may be connected. For example, fourtraces are illustrated in FIGS. 5-6. The proximal end of each trace mayoriginate at a solder pad that is compatible with a circuit connectorconventional in the art, and each trace may extend along thelongitudinal segments and transverse segments of member 212 andterminate at a different pad disposed at a different length alonglongitudinal axis 214 of member 212. Accordingly, an electrode connectedto each pad or formed from each pad may be disposed at a differentlocation along the length of member 212. Member 212 may include othertrace patterns (e.g., where the trace extends in any number of angles ordirections).

Referring now to FIG. 7, member 212 may be positioned so that thelongitudinal segments 218 of member 212 may be positioned on or aboutthe neutral axis of the catheter or sheath shaft. Accordingly, a firstpull wire 230 and a second pull wire 232 may be disposed approximately90° from an end of transverse segment 216 of member 212. This geometryand the positioning at the neutral axis may permit circuit 210 tomaintain electrical integrity and avoid shaft disruption.

As with the first and second embodiments, after each electrode isconnected to member 212 or formed from pads 226, the entire cathetershaft can be formed (e.g. reflowed with material) in order to sealand/or secure the placement of circuit 210 and the electrodes. Theelectrodes may be bonded and/or adhered to the shaft during the reflowprocess. The reflow material 234 may comprise plastic. In an embodiment,the reflow material 234 may comprise polyether block amides. In anembodiment, the reflow material may comprise PEBAX®.

Although four embodiments of this invention have been described abovewith a certain degree of particularity, those skilled in the art couldmake numerous alterations to the disclosed embodiments without departingfrom the spirit or scope of this invention. All directional references(e.g., upper, lower, upward, downward, left, right, leftward, rightward,top, bottom, above, below, vertical, horizontal, clockwise, andcounterclockwise) are only used for identification purposes to aid thereader's understanding of the present invention, and do not createlimitations, particularly as to the position, orientation, or use of theinvention. Joinder references (e.g., attached, coupled, connected, andthe like) are to be construed broadly and may include intermediatemembers between a connection of elements and relative movement betweenelements. As such, joinder references do not necessarily infer that twoelements are directly connected and in fixed relation to each other. Itis intended that all matter contained in the above description or shownin the accompanying drawings shall be interpreted as illustrative onlyand not limiting. Changes in detail or structure may be made withoutdeparting from the spirit of the invention as defined in the appendedclaims.

What is claimed is:
 1. A circuit configured for connecting an electrode to a catheter or sheath, said circuit comprising: a member having a longitudinal axis and configured to extend along at least a portion of the length of said catheter or sheath, said member comprising a first member transverse segment extending transverse to said longitudinal axis, a first member longitudinal segment extending from said first member transverse segment and extending along at least a portion of said longitudinal axis, a second member transverse segment extending from said first member longitudinal segment and extending transverse to said longitudinal axis, and a second member longitudinal segment extending from said second member transverse segment and extending along at least a portion of said longitudinal axis, wherein said first and second longitudinal segments are configured to be disposed on opposing sides of said catheter or sheath and wherein said first and second member longitudinal segments are configured to be disposed along a neutral axis of said catheter or sheath; a trace printed on said member, wherein said trace includes at least a longitudinal trace segment extending generally along at least a portion of said longitudinal axis and a transverse trace segment extending generally transverse to said longitudinal axis; and a pad integral with and extending from said member proximate said transverse trace segment, wherein said pad and said member comprise a one-piece construction, extending on said pad and terminating with said pad.
 2. The circuit of claim 1, wherein said pad extends transversely from said longitudinal axis of said member.
 3. The circuit of claim 2, wherein said pad is configured to be rolled into a ring to form an electrode.
 4. The circuit of claim 1, wherein at least a portion of said member is flat.
 5. The circuit of claim 1, wherein at least a portion of said member comprises a polymer.
 6. The circuit of claim 1, wherein at least a portion of said member comprises polyimide or polyethylene terephthalate polyester.
 7. The circuit of claim 1, wherein said circuit comprises a plurality of traces printed on said member, each of said plurality of traces including at least a respective longitudinal trace segment generally extending along at least a portion of said longitudinal axis and a respective transverse trace segment extending generally transverse to said longitudinal axis, wherein each of said transverse trace segments is located at a different location along said longitudinal axis.
 8. The circuit of claim 1, wherein said first member transverse segment is about one-half of the circumference of said catheter or sheath.
 9. A catheter or sheath assembly, comprising: a circuit comprising: a member having a longitudinal axis and configured to extend along at least a portion of the length of said assembly, said member comprising a first member transverse segment extending transverse to said longitudinal axis, a first member longitudinal segment extending from said first member transverse segment and extending along at least a portion of said longitudinal axis, a second member transverse segment extending from said first member longitudinal segment and extending transverse to said longitudinal axis, and a second member longitudinal segment extending from said second member transverse segment and extending along at least a portion of said longitudinal axis, wherein said first and second longitudinal segments are configured to be disposed on opposing sides of said catheter or sheath and wherein said first and second member longitudinal segments are configured to be disposed along a neutral axis of said catheter or sheath; a pad integral with and extending from said member, wherein said pad and said member comprise a one-piece construction; and a trace printed on said member, wherein said trace includes at least a longitudinal trace segment extending generally along at least a portion of said longitudinal axis and a transverse trace segment extending generally transverse to said longitudinal axis, said trace extending on said pad and terminating with said pad; and an electrode connected to said circuit proximate said trace.
 10. The assembly of claim 9, wherein said electrode comprises a ring or band that is separate from said circuit.
 11. The assembly of claim 9, wherein said electrode is welded to said circuit.
 12. The assembly of claim 9, wherein said electrode is connected to said circuit using a conductive adhesive.
 13. The assembly of claim 9, wherein said electrode comprises said pad formed into a ring.
 14. The assembly of claim 13, further comprising a plurality of electrodes connected to said circuit, wherein each of said plurality of electrodes comprises said pad formed into a ring.
 15. The assembly of claim 9, further comprising a first pull wire disposed on a first side of said circuit and a second pull wire disposed on a second side of said circuit.
 16. The assembly of claim 9, further comprising: a first pull wire disposed at or about 90° from an end of said first member transverse segment; and a second pull wire disposed at or about 90° from an end of said first member transverse segment.
 17. The assembly of claim 16, wherein said member may be curved.
 18. A method of forming a catheter or sheath, comprising: providing a circuit comprising: a member having a longitudinal axis and configured to extend along at least a portion of the length of catheter or sheath, said member comprising a first member transverse segment extending transverse to said longitudinal axis, a first member longitudinal segment extending from said first member transverse segment and extending along at least a portion of said longitudinal axis, a second member transverse segment extending from said first member longitudinal segment and extending transverse to said longitudinal axis, and a second member longitudinal segment extending from said second member transverse segment and extending along at least a portion of said longitudinal axis, wherein said first and second longitudinal segments are configured to be disposed on opposing sides of said catheter or sheath and wherein said first and second member longitudinal segments are configured to be disposed along a neutral axis of said catheter or sheath; a pad integral with and extending from said member, wherein said pad and said member comprise a one-piece construction; and a trace printed on said member, wherein said trace includes at least a longitudinal trace segment extending generally along at least a portion of said longitudinal axis and a transverse trace segment extending generally transverse to said longitudinal axis, said trace extending on said pad and terminating with said pad; after providing said circuit, connecting an electrode to said circuit proximate said trace, thereby forming an assembly; and reflowing a plastic material over said assembly for maintaining placement of said circuit and said electrode in said catheter or sheath.
 19. The method claim 18, wherein said plastic material comprises polyether block amides.
 20. The method of claim 18, further comprising placing at least a portion of said circuit in tubing to provide for movement of said circuit within said assembly. 